(Revised Abstract) DESCRIPTION (provided by applicant): Advances in mass spectrometry (MS) capacities and availability of complete genomes for multiple organisms have recently dramatically changed how proteins are identified and how primary sequence modifications are analyzed. Most significant, it is now possible to identify proteins from 1-D or 2-D gels or in solution mixtures at unprecedented speeds and sensitivities. Hence, during the past grant period the Proteomics Facility has been extensively expanded and modified to better meet the needs of Cancer Center members who are taking targeted proteomic approaches to cancer research or require analysis of individual proteins at low femtomole sensitivities. To better reflect the current scope and major activities of this expanded facility, the name has been changed from "Protein Microchemistry" to "Proteomics". The facility now primarily focuses on high sensitivity identifications of proteins using MS methods and also provides essential complementary analyses of protein primary structure and post-translational modifications. The following services are provided: MALDI mass spectrometry; Microbore HPLC peptide mapping; Femtomole level in-gel protease digestion; Nano-capillary LC-MS/MS based protein identification; MALDI MS peptide fingerprint analysis; Edman sequencing; ESI mass analysis of proteins. Nearly all the present equipment in the facility has been acquired during the past grant period and staff has been expanded to 4.8 FTE's. The major reason for this recent growth has been the rapidly escalating demand by Cancer Center members for nano-capillary LC-MS/MS protein identifications at sub-picomole levels from 1-D or 2-D gels of samples isolated from human cells or other organisms with complete or nearly complete genomes. Cancer Center demand for state-of-the-art MS-based analysis methods is expected to continue to grow for the foreseeable future because current Cancer Center members are increasingly shifting at least part of their research efforts to systems biology approaches using targeted or global proteomics strategies. In addition, many of the faculty who will be recruited during the next grant period are expected to have substantial needs for MS-based methods provided by the facility.